Hospitals, doctors and nursing homes have one last chance to shape a Republican bill to repeal and replace Obamacare they say will hurt millions of old, poor and sick Americans — and their own bottom lines.

After being on the sidelines for much of the repeal debate, the groups see an opening in the meltdown of the Senate health care bill. They’re particularly worried about the legislation’s proposed deep cuts to Medicaid, the country’s largest insurance program, which covers 74 million people.

Medicaid “was established to prevent our country’s most vulnerable citizens from being left behind, and it’s truly become a lifeline for millions of Americans,” said Rick Pollack, CEO of the American Hospital Association, during a call with reporters on Tuesday. “Even Republican senators are sounding alarm bells over the harm these deep cuts would cause for vulnerable patients in their states.”

A coalition of the nation’s largest provider groups is airing ads across 12 states this week linking the Senate bill to worse care for millions, including children, the disabled and the elderly. Health care lobbyists are targeting shaky senators both in D.C. and in their home states, hammering home the idea that Medicaid cuts could skyrocket charity care and force hundreds of small and rural hospitals out of business. And on Monday, the trade group representing nearly 14,000 nursing homes broke its silence to deliver a scorching indictment of Senate Republicans’ bid to remake Medicaid.

“We genuinely believe that if the senators had any idea of the extent of the impact on [nursing homes] in the country that they’d never be proposing this,” American Health Care Association President Mark Parkinson said. “If they adopt this bill, the future of long-term care as we know it will be very different.”

Insurers are taking a less combative stance, but they’re also warning that the cuts would have grave consequences. The Association for Community Affiliated Plans has released an ad criticizing the Senate plan that it says will run during MSNBC’s “Morning Joe” program. Last week, a group of 10 major Medicaid plans sent a letter to Senate leaders blasting the GOP repeal bill, arguing that it would cripple state budgets and hurt efforts to combat the opioid crisis.

“If the goal is to reform the Medicaid program and reduce costs, there are different ways of going about it than just taking a hatchet to the budget,” said John Baackes, CEO of L.A. Care Health Plan, one of the signatories to the letter.

The lobbying effort still pales in comparison to the scorched-earth tactics of the health insurance industry that derailed former President Bill Clinton’s proposed health care overhaul more than two decades ago. But the effort has been bolstered by the Congressional Budget Office’s projection that the bill would leave 15 million more Medicaid-eligible Americans uninsured over a decade, and cut federal payments to states by a quarter.

Soon after the CBO report was released, Sen. Susan Collins (R-Maine) vowed to oppose the bill unless it was made more generous. Sen. Dean Heller (R-Nev.), whose state expanded Medicaid under Obamacare, previously came out against the legislation over its cuts to the program.

That leaves Senate Republican leaders in a bind: If they soften the Medicaid cuts to placate moderates, they’re likely to antagonize conservative hardliners. That dynamic is making it difficult to arrive at a compromise that can attract 50 votes.

Senate Republicans kept such disagreements out of the headlines for weeks by drafting their repeal plan behind closed doors, vowing that it would be superior to the House version. But as soon as the draft legislation became public, those fissures came into view — and health care lobbyists were waiting to exploit the divisions.

Senate Majority Leader Mitch McConnell bowed to that reality Tuesday in announcing that Republicans would continue to work on the bill and not hold a vote before the July 4 recess — a deadline that he’d previously indicated was non-negotiable.

“Legislation of this complexity almost always take longer than anybody would hope,” McConnell told reporters. “But we’re going to press on.”

The uncertainty is likely to further embolden industry lobbyists. Even before Tuesday’s announcement, they were expressing confidence that they could prevail on key expansion-state senators in Alaska, Arizona, West Virginia and Ohio.

“This is not fine wine,” said one lobbyist, describing the unhappiness with the bill among Republicans senators. “It does not get better with age.”

Hospital groups are working closely with expansion-state governors, including Ohio’s John Kasich, Arizona’s Doug Ducey and Nevada’s Brian Sandoval, to exert pressure on senators.

The CBO score projecting coverage losses and deficit savings gave the industry groups some sense of how much they can ask for.

“Having the Senate bill provides a level of clarity we didn’t have before,” said Tom Nickels, AHA’s executive vice president for government relations and public policy. Nickels described the industry as being in “purgatory” between hammering the House bill and trying to anticipate the Senate bill.

The Senate plan notably went further than the House bill in curbing future Medicaid spending. The upper chamber would have eventually limited Medicaid spending growth per beneficiary to the consumer price index, which is far below the current growth rate.

“No element of our health care system has come close to CPI cost growth, certainly in my lifetime,” said Ceci Connolly, CEO of the Alliance of Community Health Plans. “That’s an unrealistic aspiration.”

That’s one area where Republicans might scale back the cuts. But it’s tough to see how they’re going to significantly reduce the CBO projection of 15 million fewer insured while continuing to scrap Obamacare’s Medicaid expansion.

Already, Senate Republicans have given up on making radical changes to the individual market. Their plan calls for subsidies to be available to individuals with incomes up to 350 percent of the federal poverty level, down from 400 percent under Obamacare.

That’s a far cry from seven years of campaign promises to completely dismantle the federal health care law. Despite the challenge forging consensus, Senate Republicans insist that they’ll eventually coalesce around a repeal package that fulfills that goal.

“You’re dealing with people’s lives with health care,” Sen. Marco Rubio (R-Fla.) told reporters Tuesday, after it was announced that the repeal vote would be delayed. “I’d rather do it right than do it fast. But obviously you can’t wait forever.”